1. Field of the Invention
The present invention relates to a substrate processing apparatus and a substrate processing method that keep the cleanliness of a discharge head for supplying a processing solution to a precision electronic substrate in the form of a thin plate (hereinafter simply called a “substrate”) such as a semiconductor wafer or a glass substrate for a liquid crystal display, and a nozzle arm for holding the discharge head.
2. Description of the Background Art
A substrate processing apparatus conventionally employed in a process of manufacturing substrates performs surface process of substrates including process with a chemical solution and rising process with de-ionized water, and subsequent drying process. Such a substrate processing apparatus includes an apparatus employing a single-wafer system of processing substrates one by one, and an apparatus employing a batch system of processing a plurality of substrates at the same time. Generally, the substrate processing apparatus of the single-wafer system performs process with a chemical solution by supplying the chemical solution to a surface of a rotating substrate, rinsing process with de-ionized water by supplying de-ionized water to the substrate, and subsequent spin-drying process by causing the substrate to rotate at high speed. Such a substrate processing apparatus of the single-wafer system is disclosed for example in US 2008/0078428 and in Japanese Patent Application Laid-Open No. 2010-192686, for example.
The substrate processing apparatus disclosed in US 2008/0078428 or Japanese Patent Application Laid-Open No. 2010-192686 includes a spin chuck for causing a substrate to rotate held in a substantially horizontal position thereon, a nozzle (discharge head) for supplying a processing solution to the upper surface of the substrate held on the spin chuck, and a cup surrounding the spin chuck and provided to receive the processing solution scattered from the substrate. The apparatus disclosed in Japanese Patent Application Laid-Open No. 2010-192686 additionally includes a processing chamber housing these components, and a partition plate around the cup provided to divide the processing chamber into parts, one above the other.
In the substrate processing apparatus disclosed in US 2008/0078428 or Japanese Patent Application Laid-Open No. 2010-192686, a processing solution scattered from a rotating substrate and the spin chuck may be attached to the discharge head during process. If the processing solution attached to the discharge head remains unremoved, it may drop onto a substrate to become a source of pollution, or it may generate particles after being dried. Japanese Patent Application Laid-Open No. 2004-267871 discloses a technique of cleaning a processing solution attached to a tip end portion of a discharge head by providing a large-diameter nozzle holder for discharging a cleaning solution around a discharge head for discharging a processing solution. Additionally, Japanese Patent Application Laid-Open No. 2007-149891 discloses a technique of cleaning a discharge head by spraying a cleaning solution on the discharge head in a standby pot placed outside a spin chuck.
However, a processing solution scattered from a rotating substrate and a spin chuck may be attached not only to a discharge head by also to a nozzle arm for holding the discharge head and causing the discharge head to swing. If the processing solution attached to the nozzle arm remains unremoved, it may also drop onto a substrate while the nozzle arm swings to become a source of pollution, or it may generate particles after being dried. Applying the technique of Japanese Patent Application Laid-Open No. 2004-267871 to the substrate processing apparatus of US 2008/0078428 or Japanese Patent Application Laid-Open No. 2010-192686 allows cleaning of a tip end portion of a discharge head, but does not allow cleaning of a nozzle arm for holding the discharge head. Thus, a problem relating to the nozzle arm with the attached processing solution that may become a source of pollution remains unsolved.
Also, cleaning a discharge head by using the technique of Japanese Patent Application Laid-Open No. 2007-149891 makes a cleaning solution used for the cleaning attached to the discharge head. This leads to a new problem in that the cleaning solution attached to the discharge head drops onto a different substrate to be processed after cleaning of the discharge head.